Lightning arrestor device for high power electric installations

Abstract

A lightning arrestor device for protecting an installation ( 3 ) powered by an electric transmission line ( 1 ) includes at least two assemblies connected in parallel between the line terminals, each including a disconnector (P, P′) mounted in series with at least a voltage-dependent variable resistance component. The variable resistance component is a Zener diode, at least one assembly consisting of at least two Zener diodes (Z 1 , Z 2 ) arranged in parallel.

What is claimed is:  
     
       1. Lightning arrestor device for protecting an installation ( 3 ) powered by an electric transmission line ( 1 ), comprising at least two assemblies connected in parallel between line terminals and each assembly comprising a disconnector (P, P′, P 1 , P′ 1 ) mounted in series with at least one voltage-dependent variable resistance component, characterized in that the variable resistance component is a Zener diode, at least one assembly comprising at least two Zener diodes (Z 1 , Z′ 1 , Z 2 ) arranged in parallel. 
     
     
       2. Lightning arrestor device according to  claim 1 , characterized in that the at least one of the assembly comprising at least two Zener diodes arranged in parallel presents electrical links between these diodes and the installation which are short links. 
     
     
       3. Lightning arrestor device according to  claim 1 , characterized in that one of the assemblies comprises a Zener diode of which the threshold voltage is greater than that of the Zener diodes of the other assemblies. 
     
     
       4. Lightning arrestor device according to  claim 3 , characterized in that the threshold voltage of said assembly is greater than the threshold voltage of the other assembly by a value (ΔV) equal to substantially the voltage difference between the low current value (V a ) and high current value (V b ) of the other assembly. 
     
     
       5. Device according to  claim 1 , characterized in that the threshold voltages of the respective Zener diodes (Z 1 , Z′ 1 ) of said assemblies are approximately the same. 
     
     
       6. Lightning arrestor device according to  claim 5 , characterized in that one of the assemblies comprises a Zener diode of which the threshold voltage is greater than that of the Zener diodes of the other assemblies. 
     
     
       7. Lightning arrestor device according to  claim 6 , characterized in that the threshold voltage of said assembly is greater than the threshold voltage of the other assembly by a value (ΔV) equal to substantially the voltage difference between the low current value (V a ) and high current value (V b ) of the other assembly.